Hello everyone,
We are currently starting to deal with the technical aspects of our single-family home.
I haven’t found a thread discussing whether a ventilation system generally makes sense or not. So here is a general discussion thread on the topic:
At first, we looked into various timber frame construction providers, which made us quite sensitive in this area. Naturally, a ventilation system is quite important due to the tighter building envelope, which I can completely understand. However, everything is also marketed accordingly...
Since we have now decided to go with a regional solid construction company, completely different questions arise:
I currently have a detailed offer from a solid construction company:
- $10,000 additional cost for thermal insulation measures
- $13,000 additional cost for a central ventilation system or $9,000 additional cost for a decentralized ventilation system
--> So the repayment subsidy of $18,000 is of little use to me; on the contrary, I am even paying extra for this (of course, I get a “better” house in return).
Key Data:
- Single-family home city villa, 150m² (1,615 ft²) with basement
- Air-to-water heat pump
- Building material: brick
The questions I am now asking myself:
1. Is a ventilation system even necessary to achieve KfW 55 standard?
2. If yes, would it maybe make more sense to go for KfW 70 and forget about the subsidy?
3. Is a ventilation system really that great? There are many reports about noise, high maintenance, etc.
4. If yes, in our building project would a decentralized or central system be better? I have read a lot of positive things about decentralized systems, so central ones might not be an option? Is that correct or not?
5. Is it even possible to reach KfW 55 standard otherwise? Do you really have to ventilate every 2 hours? Are there any experiences?
6. Is the additional $10,000 cost for KfW 55 without a ventilation system justified? Are the prices for the ventilation systems justified?
I know this is an endless debate and there are clearly two opinions here. However, we find it really difficult to make a decision. Maybe a few discussions and information here will help us make up our minds.
We are currently starting to deal with the technical aspects of our single-family home.
I haven’t found a thread discussing whether a ventilation system generally makes sense or not. So here is a general discussion thread on the topic:
At first, we looked into various timber frame construction providers, which made us quite sensitive in this area. Naturally, a ventilation system is quite important due to the tighter building envelope, which I can completely understand. However, everything is also marketed accordingly...
Since we have now decided to go with a regional solid construction company, completely different questions arise:
I currently have a detailed offer from a solid construction company:
- $10,000 additional cost for thermal insulation measures
- $13,000 additional cost for a central ventilation system or $9,000 additional cost for a decentralized ventilation system
--> So the repayment subsidy of $18,000 is of little use to me; on the contrary, I am even paying extra for this (of course, I get a “better” house in return).
Key Data:
- Single-family home city villa, 150m² (1,615 ft²) with basement
- Air-to-water heat pump
- Building material: brick
The questions I am now asking myself:
1. Is a ventilation system even necessary to achieve KfW 55 standard?
2. If yes, would it maybe make more sense to go for KfW 70 and forget about the subsidy?
3. Is a ventilation system really that great? There are many reports about noise, high maintenance, etc.
4. If yes, in our building project would a decentralized or central system be better? I have read a lot of positive things about decentralized systems, so central ones might not be an option? Is that correct or not?
5. Is it even possible to reach KfW 55 standard otherwise? Do you really have to ventilate every 2 hours? Are there any experiences?
6. Is the additional $10,000 cost for KfW 55 without a ventilation system justified? Are the prices for the ventilation systems justified?
I know this is an endless debate and there are clearly two opinions here. However, we find it really difficult to make a decision. Maybe a few discussions and information here will help us make up our minds.
S
Strahleman19 Jun 2020 01:29Hausi20 schrieb:
I am really glad now that I no longer have to imagine through which pipes the air I will breathe in several years passes. With a mechanical ventilation system with heat recovery, you don’t have to worry about that, since the supply and exhaust ducts are separate, and thanks to the filters in the system, the air is even cleaner than with window ventilation. My wife suffers from severe hay fever caused by grass pollen. That alone was enough reason for us to choose a mechanical ventilation system with heat recovery.
Under no circumstances should you do without a mechanical ventilation system with heat recovery in the bedroom... This is where it offers the greatest benefit. In winter, you keep the windows closed and wake up without feeling suffocated...
Another example: before going to bed, the CO2 level in our unused room with the system running is about 500 ppm, so opening the window doesn’t significantly lower it further. When waking up with the system on, the level is around 700 ppm. With the system off and windows closed, it rises to 1500 ppm or more! You can really feel this difference when breathing—it’s a huge distinction between comfortable and unpleasant...
You just need to do a little exercise in bed in the evening... After that, the CO2 level quickly rises from 500 to 1300 ppm, but the ventilation system ensures it stabilizes again quickly. Of course, you can also do a quick 10-minute airing by opening the windows, especially nice in winter.
Another example: before going to bed, the CO2 level in our unused room with the system running is about 500 ppm, so opening the window doesn’t significantly lower it further. When waking up with the system on, the level is around 700 ppm. With the system off and windows closed, it rises to 1500 ppm or more! You can really feel this difference when breathing—it’s a huge distinction between comfortable and unpleasant...
You just need to do a little exercise in bed in the evening... After that, the CO2 level quickly rises from 500 to 1300 ppm, but the ventilation system ensures it stabilizes again quickly. Of course, you can also do a quick 10-minute airing by opening the windows, especially nice in winter.
R
Rampelzampel19 Jun 2020 09:58Hello,
interesting thread, we are still sorting through the offers from various general contractors and usually there is no central ventilation system included, which I hadn’t really considered much until now. Our current favorite uses Regel-air® PLUS (which is somehow attached to the windows). Does anyone have experience with this and can say if it is effective or worthwhile? I will definitely request quotes for central ventilation systems everywhere as well.
interesting thread, we are still sorting through the offers from various general contractors and usually there is no central ventilation system included, which I hadn’t really considered much until now. Our current favorite uses Regel-air® PLUS (which is somehow attached to the windows). Does anyone have experience with this and can say if it is effective or worthwhile? I will definitely request quotes for central ventilation systems everywhere as well.
Hausi20 schrieb:
A concern for anyone prone to herpes. I’m curious. What exactly tends to show up there?
Hausi20 schrieb:
I’m really glad now that I no longer have to imagine what kind of pipes the air I breathe for several years passes through. Please be more specific. What condition are the pipes in through which you breathe air for several years?
And how do you assess the condition of the water pipes? How do you evaluate the presence or absence of accompanying substances in the water? Unlike mechanical ventilation with heat recovery, here there is no continuous volume flow—think of stagnant water.
Rampelzampel schrieb:
Our current favorite is the Regel-air® PLUS (it is somehow screwed onto the window). This is a window rebate ventilation system. In other words, we make the windows as airtight as possible and then… well, we cut slits in them again to let air pass through.
You can easily estimate the volume of air that can pass through. Just compare the cross-sectional area of all the window rebate ventilators in a room to a typical ~100mm (4 inch) valve. Then it should be clear what’s possible and what’s not.
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